Public health experts in Glasgow and Lanarkshire have warned health professionals to be on the lookout for a rare, serious condition, usually associated with cocaine use.

Three people have been treated for Methaemoglobinaemia in Glasgow.

The condition affects the carriage of oxygen in the blood.

Symptoms include blueness of the face, lips, and hands, headache, abnormal heart rate, and in severe cases, coma and death.

It is often linked to cocaine use but may have other causes.

Dr John Logan, consultant in public health medicine at NHS Lanarkshire said: "Methaemoglobinaemia occurs when an increased quantity of the iron of haemogloblin is oxidised to the ferric form.

"Essentially it means an abnormality with the carriage of oxygen in the blood.

"Investigations into the cause of Methaemoglobinaemia in these cases are ongoing, however chemicals which are sometimes added to increase the volume of cocaine are known to be able to cause the condition."

He added: "Anyone displaying these symptoms should present to their nearest A&E, GP or Health Centre for prompt assessment and treatment for what is potentially a very serious condition."